Vent Relief Sizing Help For Smaller Pressure Vessels Containing Up To 98% w/o H202 2

[MM904]

Hello,

I am attempting to purchase ASME boiler plate stamped pressure vessels for use in testing operations that require HTP. All the sources I have found discuss vent relief sizing for large storage containers, but the sizes of these tanks fall in between that of a typical lab setup of ~ 1 gallon and the drum sizing of ~30 gallons.

The propellant is not to be stored long-term, a few weeks at most. I can add additional information as necessary, but in general the hold-up on our tank design is the sizing of the vent relief valve. We are currently in contact with the HTP supplier, but things are moving excruciatingly slowly, which is why I have decided to ask for help here.

Thanks!

 

[georgeverghese]

Looks like you've got both O2 evolution and steam generation due to exothermic decomposition at concentrations exceeding 62% wt of H2O2.

http://www.h2o2.com/technical-libra...px?pid=42&name=Self-Accelerated-Decomposition

Have you found a design case basis for the decomposition rate ? What impurities would you expect to get in these vessels on worst case basis that could catalyse decomposition ?

Tread carefully I would suggest - perhaps this why the HTP supplier is dragging his feet on this ?

https://en.wikipedia.org/wiki/Kursk_submarine_disaster

 

[MM904]

The Kursk incident is the most prominent regarding use of HTP, but unfortunately there have been more. You're correct - it's potentially very dangerous - which is why I am looking to ensure that everything is done right.

I found a resource which provides a calculation for the vent area, but it requires the "rate of pressure rise resulting from 10 g test sample in the RSST/ARSST 350 ml vessel" which is data I have not found anywhere.

 

[georgeverghese]

If it helps, there is some info on decomposition kinetics at 25degC in the first link - see Gibbs free energy of dissociation. See if it is possible to derive decomposition rates for other temps from this base info.

 

[georgeverghese]

Apologies, that link only tells you the thermodynamic equilibrium constant K, which doesnt help at all with getting to the underlying dissociation kinetics.

 

[MM904]

Thanks georgeverghese, I will keep digging into the kinetics of the problem and will continue to keep looking for test results from the ARSST method that I need to calculate the vent area.

 

[Latexman]

If you can't find it (for free), contact Fauske. They have been in the business of measuring and providing this kind of data for many years. I've used them many times.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[PRVBoss]

My go to source for peroxide decomposition kinetics and relief design is a paper by Michael Grolmes of Centaurus Technology: "Pressure Relief Requirements for Organic Peroxides and Other Related Compounds" from the 1998 International Symposium on Runaway Reactions, Pressure Relief Design, and Effluent Handling. The symposium and accompanying book is a DIERS / AIChE effort. The book should be available from CCPS.

 

[moltenmetal]

If Mike Grolmes wrote it, it's likely to be both practical and as close to right as you're going to get.

 

[Latexman]

PRVBoss, a star for you!

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.